This invention relates to a suspension spring assembly for motor vehicles and is particularly concerned with a support of elastic material for the end coil of a helical spring of the suspension. The seating face of the support has a helically ascending course.
Helical springs are mass-manufactured as suspension springs for supporting the body of a motor vehicle. These springs are made of wire which is usually wound about the spring axis with a constant coil diameter and with a uniform slope (helix angle) over the entire springing zone. All springing coils of a linear, cylindrical helical compression spring contribute the same amount to the entire spring path because, due to their identical helix angles--and thus identical pitch--they remain fully effective until they all block simultaneously, that is, the coils do not contact one another earlier. In addition to the effective (springing) coils, the springs also include non-springing (dead) end coils which are to transfer external loads from the associated spring seat discs to the springing coils in as centered a manner as possible (that is, the axis and the line of action of the spring preferably coincide). Generally about 3/4 of one coil is provided for this purpose at each end of a spring, so that the contact areas each extend over a winding angle of about 270.degree.. In most cases the end coils have, even in the unloaded installed state, an approximate pitch which corresponds to the wire diameter, while the effective (springing) coils have a greater pitch (slope).
Usually, the spring end of prior art arrangements rolls off on the spring support as the point of disconnection, that is, the location where the spring end lifts off from the support, changes to a greater or lesser degree dependent upon the spring force (vehicle load). Thus, one part of the spring end rests on the support only at times. As a result, on the one hand, the customary anticorrosion coating of the spring will be destroyed at this spring part because of the occasional rolling action and, on the other hand, water can splash and dirt can penetrate between the support and the spring, thus causing an increased corrosion.